Apparatus and process for reducing and refining ores



April 29 1924. 1,491,960

E. MILL APPARATUS AND PROCESS FOR REDUCING AND REFINING ORES Filed Sept.28 1920 IIII/IIIIII l INVENTOR, 1? M1115 Q ATTORNEY Patented Apr. 29,1924.

NITED; STATES PATENT OFFICE.

EIIL HILL, 0!- ANGELES, CALIFORNIA, ASSIGNOB OF ONE-HALF TO ALTHEBTON L.

GRAY; OF L08 ANGELm, CALIFORNIA.

APPARATUS AND FOR REDUCING AND BEFINING ORES.

7 Application flledSentember 28, 1820. Serial No. 418,852.

To all whom it may concern:

Be it known that I, EMIL MILL, a c1t1zen of the United States, residingat Los A11- geles, in the county of Los Angeles and State of California,have invented new and useful Imfprovements in A paratus and Processes orReducing and fining Ores,

of which the following is a specificatlon.

. able to ores mined in Western States. 'It

has been found that European ores and ores found in Eastern Statessometime require particular methods in refining and reducing same. Theinvention has for an obf'ect the turning of oxides of iron into metal iciron. Another object is the production of an a paratus and processforproducing metal 1c llOIl in a more direct, inexpensive and quickmanner than is now possible by existing known means. a y

In racticing theinvention I provide a suitab e hopper or container intowhich iron ore, broken into small pieces, may be placed. Associated withthe lower portion of said hopper are valve means spacedly dis osedwithin a duct, which duct joins, wit the chamber of a retort. c The ironore is rmitted' to pass through the duct and into the chamber and thencethrough pipes-joining the lower 'wall of said retort with a furtherretort spaced from said upiper retort. Surrounding both the upper anlowercretort members is a wall of fire clay orother heat resistingmeans, and playin through apertures within the fire c ay we 1 or heatresisting wall are nozzles through which gas may be assed. Said gaswhen'ignited allows a ame to play on the outer surface of the lowerretort and by conduction allows the heat to pass within the retort.Within the lower retort are spacedly arranged a plurality of electrodes.Said electrodes depend through apertures in the upper wall of said lowerretort. The electrodes are preferably made of graphite and are providedwith a longitudinal bore through.

which bore a carbonaceous gas is assed; The electrodes are likewiseprovide with electrical contacts and electrical circuit paths connectwith said contacts. The bottom wall of the lower retort is providedbonaceous gas is bein with depending pipes having spaced valves therein,the stretch between the upper valve and lower valve being provided withmeans for feeding a-carbonaceous as therein. The division etfectedbetween t eupper retort and lower retort by pipes joining the same inspaced relation to each other is necessary in order that an operator mayremove any ofthe lower retort may also heat'the upper retort, conductingpipes extend between the er baflie plate and lower bafile plate;

'l us method of heating the upper retort allows for a graduallyincreasing heat, as any ore contained within the upper retort passesdownwardly through the pipes above mentioned into the lower retort. Thearticular arrangement of the electrodes al ows for a heating within thelower retort, and

when a low potential current is effected be-' tween theelectrodes an arcappears, which arc is not sufiicient to in any wayfuse the me withinsaid retort. Inasmuch as a carheated electrodes, I be ieve that the gaswill tend to absorb more carbon and thus when discharged from the openinin saidelec trodes, the as will be in a ighly nascent state, readicombining with any oxygen confined wit in the ore and formin a carbondioxide gas, and leaving metal 1c iron,

which is coated with carbon deposit throughout the voids of said iron.

Ordinarily inreducing iron ore, a blast of air is forced throu h the orewhen the ore is heated, but in t is invention all air is excluded fromthe retorts. I believe that it is a commonly known fact that ore of allforms, and particularly iron ore, has a great deal of air confinedwithin the same, and by heating the ore as has been described, the oreW111 crack, similar to the method of cracking" oil to produce gasoline.This cracking of course allows the im risoned oxygen and other sesconfined within the ore to escape an immediately upon its escape the carnaceous gas which is introduced within the retort may combine withpassed through the the same forming another gas of some complex chemicalcomposition and allow carbon to be deposited over the iron and in allinterstices, pores and voids of the iron.

It is a so known that any iron when heated to a high temperature andexposed to the atmosphere before allowing it to cool, the same mayimmediately oxidize. However, by the method just described theiron maybe removed from the retort, and due to the fact that it is coveredthroughout with carbon the metallic iron will not rust or oxidize.Obviously the metallic iron removed from said retort will not requirefurther carbon in the making of the same into steel. In fact, the oreremoved may be again heated to the desired temperatures and the carbonpresent will be sufiicient for steels of various forms. It willimmediately be seen that this eliminates two operations ordinarilyincident to the making of steel.

The invention has for further objects to provide a process as well asapparatus of the character above mentioned which will be relativelysimple and inexpensive in carr'y ing on or practicing or furtherance,taken in conjunction with efiiciency and expediency and generaladaptability.

The invention consists in the novel and useful means and processhereinafter disclosed, and finally pointed out in claims.

It will be understood that many variations in detail may be made indeparture from the specific definition of the rocess as well as theapparatus about to disclosed.

In the drawing:

Figure 1 is a cross sectional view of a furnace which may be utilized inreducing and refining ores;

Figure 2 is a fragmentary cross sectional view of an electrode used inpracticing the invention;

Figure 3 is a fragmentary perspective view of a valve used in connectionwith the invention;

Figure 4 is a fragmentary cross sectional view of a trap door used inthe ducts; and

Figure 5 is a fragmentary view of a filtering device used in practicinthe invention.

Corresponding parts in al the figures are designated by the samereference characters.

Referring with particularity to the drawing, A designates the completedfurnace of which 1 is a hopper into which the broken pieces of ore suchas iron oxide a may be introduced. The hopper has its bottom wall memberI) slanting downwardly, so that the ore a within the hopper 1 will tendto move toward one point as 0. At said point there is an openingprovided with a duct 3. The duct 3 has adjacent the opening 0 a slidingdoor valve- 2 which is illustrated in Figure 3, in

which figure it will be observed that the surface thereof and whichboxing 2 is a part of the valve 2. Passing through said oxing is a handscrew 2" provided with threads, the lower stretch of which as 2 hasconnected therewith a circular door 2". The duct 3 is slotted as at 3 asufficient width so as to permit the door 2 to be drawn through the sameupwardly or downwardly dependent upon rotation of the means 2". Thisarrangement permits closing the duct 3 at its upper end and prevents anyof the ore (1. within the hopper 1 from entering said duct. The duct 3asses through a plate (1 into the interior 0 a retort 5. Just above saidassage into the retort 5 is located a furtlier valve 4 which in allparticulars is similar to the valve 2 just described. It will thus beseen that in order to properly introduce any ore a from the hopper 1into the retort 5 and the chamber 5 thereof, it will be necessary firstto raise the valve 2 allowing the ore to pass into the space 3' betweenthe valves 2 and 4, at whichtime the valve 2 has its gate 2 screweddownwardl so as to close the opening in the duct 3, an then the valve 4is so screwed that the gate of the same will be raised and the contentswithin the space 3" allowed to ass into the chamber 5 of the retort 5. epurpose of all this is to prevent the atmosphere from directly enteringthe retort 5. It will be noticed upon reference to the drawing that theretort 5 is provided with openin s5" through its lower wall 5, and intosaid 0 enings 5" are passed and confined pipes 6. he pipes 6 are ofextended length and communicate with a lower retort 7 through openings 7in the upper wall 7 of said retort 7. Pipes 6 likewise pass through whatmay be termed bafile plates e and f. The upper plate 6 joins the bottomplate of theretort 5 on the exterior thereof as at 5 and the bottom latef joins with the top wall on the exterior t ereof as at 7 of the retort7. These plates 6 and f are preferably circular in formation, although Ido not wish to be restricted to this particular contour. The lowerretort wall 7 of the retort 7 has dependent through holes 7 thereinpipes 9.

The pipes 9 are similar to the duct 3 previously described, and saidpipes 9 are provided with upper and lower valves 8 and 11 arranged inspaced relation each to the other. The valve 8 is arranged a shortdistance below the opening 7 and the valve 11 is arranged adjacent anend 9 of the pi s. The space confined-intermediate the valifes 8 and 11as 9" has communicating therewith a pipe 10. Said pipe 10 normallyconducts a carbonaceous gas to the space 9 of the pipes 9. The lower endof each of the pipes 9 is provided with trap doors 12. Said tra doorsare illustrated in Fi re 4, in whic it will be noticed that the 001' 12is hinged duct 3Thas a boxing 2 formed on the outer to the pipe 9 as at12 by means of a strap 1 i which hook projection engages with a leafthereof an spring 12' attached at one end as 12' to the 1pc 9. Thus thetrap door may beopened y releasing the spring 12? from the projec'tion12, or the "tra door 12 vmay be readily snapped into position.Surrounding the outer periphery of. the plates e and f as well as theretorts 5 and 7 and the pipe6, is a circular wall 13. Said wall 13extends upwardly and joins with the late (1 -as shown at g. A lowerportion said wall 13, as 13 does notcompletely endose the retort 7 butallows a. lower stretch of the same as 7 to be exposed. The retorts and7 are each in spaced relation to, the inner wall surface of the wall13.v The wall 13 is preferably made of fire clay rovided with a tilelining, although the wal may be made of any heat resistant material.Extending between the plates e' and f and communicating with the s acebetween the wall 13 and i the outer sur ace of each of the retorts 5 and7, are pipes 14. Passing through perforations 15 located as at 16 in thewall 13 are nozzles 17 through which is conducted by means of pipes 18,a gas of some form suitable, when ignited to heat the outer wall surfaceof the retort 7. Obviousl the gas flowing within the space confinebetween the retort 7 and the wall 13 will tend, when ignited, to presenta solid flame completely around the retort 7. Of course oxygen for ropercombustion will be drawn upwardly into thespace for thereason that thewall 13 terminates so as to permit air to be drawn u wardly into saidspace, as shown at 19.

e heated air and ases will surround the chamber 5 and heat t e same.From thence the heated gases are allowed to pass upwardly throu h astack 20 confined within a hole 21 in the wall at as at 22. A damper 23regulates the out-ward flowof the heated gases to -,the atmosphere. Itwill seen that the retort 5 is really pre-heated and does not have aflame playing against the same. i

Depending within the lower retort 7 through a ertures in the upper wall7" through apertures 'in the wall 7 are electrodes 24. Said electrodes24 are arranged in a spaced relation each to the other as shown in thedrawin Referrin to' Figure 2 it W1 1 be seen that the electro cs 24 aretubular information or provided with a lon itudinal bore 25 concentricwithin said e ectrodes 24. The electrodes are preferably made ofgraphite, and

surrounding an upper stretch of said electrodes as zit-26 is a cop nband 27 provided with ears 28 for c amping the band to the electrodes24. Through said ears a screw 29 is passed for firmly securing the band27 to the electrodes 24. A short pipe 30 communicates with the bore 25as'at 31. Said pipe is likewise attached by suitable means as 32 to anon-electrical conducting tube or ipe 33. Referring to igure-l thenon-con ucting tube or pipe 33 passes upwardly and is capped or closedas at 34. Likewise it is joined to the wall e as at 34 so that theelectrodes 24 may be retained in position. A pipe 36 passes throughperforations in the walls 13 and 37 and connects with an enclosedbox-like structure 45. Said pi e 36 likewise connects with each of thetuhes 33 as "at 36. The boxdike structure is suitably supported by meansof a bracket 46. Said bracket 46 is located exteriorly of the wall37-and is held to same by means of rivets. A further pipe 47communicates with the interior of' the box 45 as at 48. Within'the box45 are small carbon granules 49. Where the ipes 36 and 47 enter the boxis placed a brous cloth 50. The pipe 47 connectswith the source ofsupply for a carbonaceous gas. Beneath the bracket 46 is a heatins.means 51 provided with a jet. A pipe 52 connects said jet with a sourceof gas supply. It is the intention to light the jet 51 and heat-the box45. It will thus be seen thatthe carbonaceous gas first passes throu hthe'pipe 47, through the cloth 50, then t rough the carbon granules 49within the box 45, then through a further cloth, and then into the pipe36 and down through the bore in the electrodes 24 into the retorts 7.

Electrical conducting paths such as wires X are joined to each of theelectrodes 24 at the ears 28 of the band 27. The electrical conductingwires X are connected with a source of electrical supply 35 of lowpotential. Two parallel walls 37 arranged in spaced relation each to theother, normally support the wall (1, the wall 13. and the hopper 1.support the entire furnace, inasmuch as'the plate members e and areembedded within the wall 13. When t 1e furnace is in operation a gassuch ascarbon dioxide is driven oif from the oreand said gas is allowedto pass through a pipe 38 communicating with the interior 5 of theretort 5. 'Sa-id pipe has at an upper end as at 39 an automatic pressurevalve 40 which allows the burnt or waste gases to escape through thesame and into the-pipe 41 passing withinthe stack 20 as at 42. Theautomatic pressure valve 40 permits any: gas to escape from the retorts5 and 7, but does not permit any air passing back into the'same.

The walls 37 are supported as at 43 upon a suitable foundation 44.

The operation is as follows:

Thus the parallel walls 37 tend to The ore is first introduced in smallchunks is then closed and the valve 4 opened and the ore passed into thechamber 5% of the retort 5. From thence the ore passes through the pipe6 into the retort 7 and then the same may be passed through the pipe 9by opening the valves 8 and 11.

First the gas used for heating the exterior of the retort 7 is ignitedat the nozzle 17 and as the flame plays around the retort 7 the retortis heated, and the heated gases allowed to pass upwardly through thepipes 14 and heat the retort 5. Ore is introduced within the retorts 5and 7 so as to completely fill the same, and as it is necessary thateach piece of ore go through the same operation it is essential that theore confined within the retort 7, to begin with, be drawn off throughthe pipes 9 and again placed in the hopper 1. Obviouslycthe ore alreadywithin the retort 5 will not be again placed in the hopper 1. As theflame plays around'the retort 7 electricity is passed through theelectrodes 24. and while so-passing an arc will be formed between theelectrodes. This are is of low potential and not sutiicient to fuse anyore within the retort 7. Obviously the arc will tend tolieat theinterior of the retort 7- and while the electrodes are so heating theore in combination with the heat being absorbed through the wall of theretort, a carbonaceous gas is passed through the bore of the electrodes.The temperature within the retort 7 is preferably maintained at 1100degrees and this amount of heat I believe tends to cause the electrodes24,

which as has heen stated, are .formed of graphite, to be in a state-ofagitation; that is, the molecules of carbon making up the electrodes24am in a vibratory state, and as the carbonaceous gas passing throughthe same is heated by the electrodes the gas I 'believe tends to absorbmore carbon and thus becomes satu'rated. with carbon and in a highlyunstable'and nascent state.

It will be seen that as the ore asses'from the chamber 5* of the retort5 ow'nwardly into the chamber portion of the retort 7, that the ore willggadually become heated more and more, andwhen in the" retort .7 theheptissufiicient to crack the ore.- It wilt now be obvious why a doublesystem-of; valves as 2, 4, 8 and 11- is employed. They are employed inorder to keep out the atmosphere from the retorts 5 and 7. I am of theopinion that all ores contain a certain numberof gases and when the orecracksthe gases are released and which gases immediately combine, Ibelieve, with the carbonaceous gas and in so combining carbon isdeposited in the voids of the ore, effectively sealing the ore against are-introduction or re-oxidization of the ore. Obviously when the furnaceis in o ration the valve 2 is first lifted, the ore al owed to pass inthe space 3 of the duct 3, the valve 2 closed, and the valve 4 again incase the same has not ore.v is practically fact, by using the h ter amore perfect product ofiron is produced.

been reduced and refined may not oxidize en properly covered with carbonthroughout its voids. further carbonaceous gas is introduced into thespace 9 through the pipes 10. Upon opening the valve 11 the ore may bepermitted to drop downwardly and into the open when the trap door 12 isreleased.

Obviously any impurities within the iron ore would be burnt by the heatwithin the retort 7 and the burnt gas allowed to escape upwardly throughthe pipe 38 and then into the stack 20. g

It will be noted that the wall 13 is cut out between the plates 6 and Inactual practice of the invention a plurality of furnaces similar to thatshown in Figure 1 is included between the parallel wall members 37.Inorder that an operator may successfully replace worn-out electrodes 24it is essential that the operator be permitted to pass within the spaceconfined between the plates 6 and f to further similar spaces induplicate furnaces.

It has been found that little slag is formed when a filter means such asthe box 45 containin carbon granules 50 therein is employe The inventoris not sure as to the exact chemical re-action occurring within theretorts 7 and 5. However, when the carbonaceous gas is passed, throu hwhat is termed the filter, thence throug the electrodes 24 and then intothe retorts 7 and 5, thegas in some manner is more active, and anysilicon or sulphur within the iron is immediately burned out and theresultant ure metallic iron. In

' It is manifest that man variations and changes may be made wit respectto the disclosure of the foregoing furnace in connection with theparticular method of refining ores such as iron ores, just described,

within a fair spirit of interpretation of the invention. I

Having thus disclosed my invention, I claim and desire to secure byLetters Patent: i

1. The. herein disclosed method of reducin and refining iron ore withinthe workho ding retort of a furnace, which consists inintroducing heatexteriorly jand interiorly of the retort so as to heat the ore and cracksame; passing a carbonaceous as within the retort and preventing access0 other oxygen than that already present within the retort and ore.

2. The herein disclosedmethod of reducin and refining iron ore within aworkho ding retort of a furnace, which consists in introducing heatexteriorly and interiorly of the retort so as to heat the ore and crackthe same; passing a super-heated carbonaceous gas within the retort andpreventing the access of other oxygen than that already resent withinthe retort and ore, thus alowing the carbonaceous gas to combine withthe oxygen resent and at the same time to fill all the interstices andvoids of the ore with a deposit of arbon, thereby preventingre-oxidization of idiaore,

3. The art of reducingand refiningores, which consists in placing ore ina retort, heating the ore by application of heat both exteriorly andinteriorly of the retort, injecting a carbonaceous as into the retort,and preventing access 0 other oxygen than that in the ore during theprocess.

4. The art of reducing and refining iron ore, which consists in placingthe ore in a retort, heating certain portions of the retort bothexteriorly and interiorly so as to subject the ore from a known minimumto maximum heat suflicient to crack the ore, preventing the access ofoxygen within the retort and introducing a carbonaceous gas within theretort.

5. The art of reducin and refining iron ore, which consists in p acingthe ore in a retort, heatin certain portions of the retort bothexteriorfy and interiorly so as to subject the ore from a known minimumto maximum heat suflicient to crack the ore, preventing the access ofoxygen within the re tort and introducing a carbonaceous gas within theretort which has first been allowed to flow through heated carbon.

6. A furnace forreducing and refining ores, comprising an upper and alower retort spaced from each other; ipes communicatin with the chambers0 said retorts, means for directly heating the lower retort andindirectly heating the upper retort so that there is a progressivelyvarying heat upwardsin the, chambered portion of the lower and upper.retorts; means for introducing a carbonaceous gas into the upper retort,and means forpassin said gas in a superheated condition into t e lowerretort chamber.

' 7. A furnace, comprising upper and lower retorts in spaced relation toeach other,

intercommunicating means joining the chambers of said retorts, an outerrefractory wall spaced from the retort walls, said lower retort wall andrefractory wall forming between them a continuous combustion space,means for supporting combustion in said combustion space, whereby thelower retort wall is heated; and means for supplying a carbonaceous gasto the space confined by said upper and lower retort walls.

8. A furnace, comprising upper and lower retorts in spaced relation toeach other, intercommunicating means joining the chambers of saidretorts, an outer refractory wall spaced from the retort walls, saidlower retort wall'and refractory wall forming between them acontinuous'combustion space, means for supporting combustion in saidcombustion space, whereby the lower retort wall is heated, means forconducting the heated gases of combustion to the space confined by theupper retort wall and refractory wall so as to heat-the upper retortwall,

and means for supplying a carbonaceous gas, etc.

9. A furnace, comprising an outer wall of refractory material, an innerretort wall spaced. therefrom, said walls forming between them acombustion space; means for supporting combustion in said combustionspace; means within said retort for heating said retort; and means forsupplying a carbonaceousgas to the space confined by said retort wall.

10. A furnace, including upper and lower retorts in spaced relation toeach other; an outer refractory wall spaced from the retort walls, saidlower retort wall and refractory wall forming between them a continuouscombustion space; a plate joined with the upper wall of the lower retortand embedded in the refractory wall dividing the lower retort from theupper retort; means for supporting combustion in the combustion space,and means for supplyinga carbonaceousgas to the space confined by saidupper and lower. retort walls; there being intercommunicating meansjoining the chambers of said retorts.

11. A furnace, including an outer wall of refractory material; platemembers arranged in spaced relation embedded in said wal and dividingsame into compartments; a retort interposed between two of. said platemembers with the walls of said retort spaced from said outer wall, alower retort dependent from another of said plate members, said lastnamed retort being in spaced relation to the outer wall; interconmunicating means joining the chambers of said retorts, and means forheating said retorts.

12. A furnace comprising an outer wall of refractory material, an u p'erand a'lower retort confined within said outer wall and in spacedrelation thereto, inter-communicating means joining the chambers of saidwith said last named means for preventin access of any air while passingsaid worfi to said retort.

13. A furnace comprising an upper and lower retort, intercommunicatingmeans joining the chambers of said retorts; a hopper located above saidupper retort and means joining said hopper and chamber of said upperretort whereby any work within said hopper may be passed into said upperretort; said means joining the hopper an upper retort being providedwith means for preventing the access of air from the outside into thesand retort; means likewise being provided for introducing acarbonaceous gas within the chambered portions of said retorts.

14.- A furnace comprising an upper and lower retort, intercommunicatingmeans joining the chambers of said retorts; a hopper located above saidupper retort and means joining said hopper and chamber of said upperretort whereby any work within said hopper may be passed into said upperretort; said means joining the hopper and upper retort being providedwith means for preventing the access of air from the outside into thesaid retort; means likewise being provided for introducing acarbonaceous gas within the chambered portions of said retorts; meanslikewise being provided dependent from a bottom wall of said lowerretort for removing any work contained within said retort and meansassociated with said last named means for preventing the ingress of anyair while removing any work from the retort.

15. A furnace, comprising a work-holding retort, means within saidretort for heating the same, means for introducing a carbonaceous gaswithin said retort, and means for filtering said gas before itsintroduction within the retort.

16. A furnace, comprising a work-holding "retort, means within saidretort for heating the same, means for introducing a carbonaceous gaswithin said retort, and means for filtering said gas before itsintroduction within the retort; said means for filtering said gascomprising a container filled with carbon granules, around whichgranules the gas first passes before its introduction into the retort.

17. A furnace, comprising a work-holding retort, means within saidretort for heating the same, means for introducing a carbonaceous gaswithin said retort, and means for filtering said gas before itsintroduction within the retort; said means for filtering .said gas comrising a container filled with carbon granu es, around which ranules theEMIL MILL. Witnesses i Mimnm Luca, J, CALVIN Brown.

furnace, comprising a work-holding

